How to identify canker sores.
Canker sore / Aphthous ulcer identification.
Dentists distinguish canker sores (specifically, “recurrent minor aphthous ulcers” which are the type of canker lesion that affects 80% of sufferers) from other types of mouth sores by way of:
- Their appearance during their progressive stages of formation and then healing.
- Their location and the type of oral tissue on which they’ve formed.
- The fact that they are recurrent (meaning they have been experienced by the person before).
Additional information sources.
A person’s Patient History also plays an important role in canker identification and helping to differentiate these sores from other kinds of lesions Like Herpes..
Various signs and symptoms that did or specifically did not take place, both immediately before, or throughout the stages of their ulcer’s formation and healing process, can be valuable aids in arriving at an accurate diagnosis. (The link above provides further details.)
Methods that aren’t typically used.
As a side note, we’ll point out that no medical testing (e.g. biopsy, culturing) is typically involved in making a diagnosis. The findings and factors mentioned above, collectively, are usually all that’s needed to make an accurate diagnosis.
We’ll also mention that when viewed microscopically, the visible characteristics of canker sores are non-specific and therefore this method of examination isn’t especially useful in lesion identification.
(Visit this page if you’d like more information about The biology of canker sore formation. )
What do canker sores look like? – The stages.
Note: The time frames we’ve assigned to the different stages outlined below overlap, due to the fact that what is experienced by any one person varies.
Stage 1 – (2 to 48 hours duration)
The earliest indication of pending canker sore formation doesn’t involve visible signs.
Instead what is noticed is a sensation of tingling, itching, burning, or numbness in the area where the lesion will ultimately form. (These signs are referred to as “prodromal” symptoms.)
Stage 2 – (18 to 72 hours duration)
During this time frame, the first visible signs of the developing lesion will have started to show.
- The area where the sore will form begins to transform into a reddened circular area on the skin. (Formally referred to as an “erythematous macule.”)
- As the lesion’s development progresses, the macule may transform into a small, possibly whitish, papule (solid, slightly raised area).
- During this stage, the area will begin to ulcerate and enlarge. (The process of ulceration begins in the skin’s basal layer and then advances into the more superficial layers above.)
Pictures of canker sores (aphthous ulcers).
Stage 3 – (1 to 14 days duration)
Appearance (of the typical fully-formed canker sore).
- In basic form, the lesion is a single shallow ulcer having a symmetrical round or oval shape. (Multiple simultaneous lesions are possible.)
- Canker sores are typically no more than 1/4 inch in diameter (3 to 5 mm).
Diagram: The physical characteristics of a canker sore.
Sores have a grayish membrane-coated central ulceration with a surrounding red border. The skin around the lesion looks normal.
- The lesion’s center (the ulceration) develops a loosely attached membrane-like covering (a pseudomembrane) that can be easily dislodged.
(The membrane is pyogenic in nature, meaning it’s composed of cells, compounds, and debris originating from the inflammatory process that has caused the ulceration.)
- Initially, the membrane has a primarily yellow-white coloration. As healing ultimately progresses, it will tend to take on more of a grey-white tint.
- A border comprising a band of erythematous (reddish) tissue will surround the ulceration.
The outline of this red halo is characteristically circumscribed (well defined) and regular (not jagged).
- The skin that lies outside the lesion’s reddened border will appear normal and healthy.
Other characteristic signs and symptoms.
- Canker sores usually are painful. The level of discomfort that’s experienced may seem out of proportion with the lesion’s size.
Sufferers will frequently limit their oral movements, the types of foods they eat, and favor the sore’s surface so not to trigger pain.
- There are no distinguishing systemic features associated with minor aphthous ulcers, such as the person having malaise (generally feeling poorly) or fever.
Can a person have more than one lesion at a time?
Yes, outbreaks of multiple, simultaneous canker sores may occur.
- Usually, the maximum number of sores that will form at one time will be six or fewer.
- If multiple canker sores do develop, they’re more likely to be distributed as opposed to being clustered together.
- In the case where two sores do form adjacent to each other, they may combine into a single larger and irregularly shaped ulcer (as opposed to the classic round or oval shape).
▲ Section references – Neville
Are they contagious?
- No, canker sores are neither contagious nor infectious.
For more details, see this page Why canker sores are not contagious.
Where do canker sores form?
They characteristically only form on the “loose” (movable) tissues of the mouth, meaning those areas where the skin is not tightly bound to the bone underneath. These locations generally involve the “nonkeratinized” (softer, less tough) tissues of the mouth.
Location, location, location.
An important aspect of canker sore identification is based on the fact that they characteristically only form in certain parts of the mouth. These locations are, listed here in order of locations/tissues most affected:
Diagram: Locations where canker sores usually form.
Canker ulcerations characteristically form on the “loose” tissues of the mouth.
- The inside surface of the lips and cheeks.
- The underside (ventral surface) of the tongue.
- The mucobuccal fold (the deep trough where the skin of the jawbones and lips/cheeks meet).
- The floor of the mouth.
- The soft palate.
- The tonsillar areas.
(Listed in order of locations/tissues most affected.)
Less common locations.
While rare, it is possible for canker sores to form on keratinized tissues. This includes the top (dorsal) surface of the tongue, the gum tissue that surrounds a person’s teeth, hard palate, or even the border of the lips (vermilion border).
▲ Section references – Neville, Dunlap
Canker sore healing.
How can you tell if your canker sore is healing?
The normal uneventful healing of canker sores is usually gauged by their healing time frame and appearance.
Healing time frames.
Canker sores (recurrent minor aphthous ulcers) characteristically heal within a limited time frame and therefore the duration associated with their healing progress can be used to help confirm the identity of a person’s lesions.
- A sore will usually heal within 4 to 14 days, although some can heal in as little as 3 to 5.
The pain associated with the lesion usually begins to subside around days 3 to 4.
- In most cases, healing is uneventful and results in no residual scarring.
- Any ulcer that has not healed within a 2-week time frame should be evaluated by a dentist.
This is for two reasons. One is for proper lesion differentiation. (Is the lesion really a canker sore?) The other is because there is another larger, more problematic form of aphthous ulcer that characteristically does have an extended healing time frame and its management is different than with common, limited canker sores.
- New skin growth (epithelialization) will begin at the edges of the ulceration and then close in from all directions as the healing process progresses.
- The original yellow-white coloration of the pseudomembrane that covers the ulceration’s surface will transform into a more grey-white appearance as the epithelialization process advances.
Of course, this covering will be gradually replaced at its edges by new pink skin as the size of the lesion shrinks.
- The reddened border of the original wound will remain obvious during the early stages of the healing process. Then, as the new skin tissue matures, the border’s redness will fade. Complete healing and a normal appearance will return to the affected area within the time frame stated above.
How do you know that your canker sore is healing properly?
As long as the changes you notice with your lesion’s healing progress stay within the time frame and appearance parameters just discussed, you can assume that all is correct and proper about its healing process. And in a relatively short amount of time (less than two weeks), this current outbreak of lesions should just be a nuisance that’s since passed.
Any variance from what’s described above should trigger some concern and is a reason to consult with your dentist. Top on the list of issues that should be investigated is if the lesion is indeed a canker sore (“recurrent minor aphthous ulcer”), as opposed to a lesion of a different cause.
If the lesion is determined to be an aphthous one, your dentist should then determine if instead of a “minor” lesion it is a “major” one. And therefore a type of sore that needs an extended time frame and possibly more aggressive management to resolve.
How often do canker sores form?
Another important aspect of canker sore identification involves correlating characteristics associated with their occurrence.
- Once a person has experienced an initial outbreak, the probability of recurrence is high, although the frequency with which this takes place can be quite variable.
- A rate of one outbreak every 1 to 3 months might be considered typical (encompassing about 50% of people who get them). 30% of sufferers deal with their presence on a monthly basis.
That means many people will only be plagued by a few episodes a year, while others will experience nearly continuous outbreaks and therefore will never be completely free of ulcers for any extended period of time.
Incidence rates / Prevalence.
- Most sources tend to suggest that around 20% of the general population experiences canker sores, although actual reports from studies have ranged from 5% to 66%.
- A person’s first outbreak will typically take place between the ages of 10 and 20 years, and then decrease in frequency and severity with age.
Lesions are most prevalent in people ages 10 to 40. 80% of those affected will experience their first lesion prior to the age of 30.
- It’s been suggested that women are more likely to experience sores than men but not all studies confirm this fact.
- A family (genetic Details) predisposition seems to exist. Children with parents who get canker sores have a 90% chance of getting them too, as compared to a 20% chance for those whose parents don’t.
- A person’s risk seems to be unrelated to race. But people who live in North America are more likely to suffer from them, as opposed to people who live in other worldwide geographic areas.
- Non-smokers and people in upper socioeconomic groups are more likely to experience outbreaks.
What are “major aphthous ulcers”?
Canker sores like we have described above are formally termed “recurrent minor aphthous ulcers.” They are the type of canker lesion experienced by 80% of sufferers.
Beyond these “minor” lesions, there’s another type of aphthous ulcer referred to as “major aphthae” or Sutton’s ulcers. And in comparison to the minor variety, they are large, deep ulcerations whose healing is characteristically slower and more painful.
- Unlike minor aphthae, the major kind forms on all types of oral tissues (both keratinized and nonkeratinized tissues). They frequently form on the lips, soft palate, or fauces of the throat.
- They can approach 1/2 inch (or more) in diameter and may cause regional or even facial swelling.
- Their healing usually takes between 10 and 40 days. However, it may take some months (even as new ulcers are forming).
- Healing is often associated with scarring.
▲ Section references – Chavan, Neville
Page references sources:
Akintoye SO, et al. Recurrent aphthous stomatitis.
Casiglia J. Recurrent aphthous stomatitis: Etiology, diagnosis, and treatment.
Chavan M, et al. Recurrent aphthous stomatitis: a review.
Dunlap CL, et al. A guide to common oral lesions.
Neville BW, et al. Oral and Maxillofacial Pathology. Chapter: Allergies and Immunologic Diseases.
Scully C, et al. Oral medicine — Update for the dental practitioner Aphthous and other common ulcers.
Ship J, et al. Recurrent Aphthous Stomatitis.
Ship II. Epidemiologic aspects of recurrent aphthous ulcerations.
Woo S, et al. Recurrent Aphthous Ulcers: A Review of Diagnosis and Treatment.
All reference sources for topic Canker Sores.